Many important enzyme-catalyzed reactions involve nucleophilic substitutions at the carbon-oxygen double bond. It has been suggested by Deslongchamps that steroelectronic control plays an important role in those enzyme-catalyzed reactions that proceed through tetrahedral intermediates. Because of its close relationship to the carbon-oxygen double bond, we propose to evaluate the importance of stereoelectronic control in the reaction of compounds containing a carbon-nitrogen double bond. The kinetics and mechanisms of nucleophilic substitution reactions in compounds of type R1 (X) C=NOR2 will be investigated. In order to study the stereochemistry of these reactions, compounds containing configurationally stable C=N bonds will be synthesized. The following reactions will be investigated, (1) 2,2,2-trifluoroethyl (Z) and (E)- hydroximates (X = OCH2 CF3) with methoxide ion; (2) (Z)- and (E) - hydroximoyl chlorides (X = C1) with azetidine; (3) (Z)- and (E)- hydroximoyl cyanides (X =CN) with methoxide ion; and (4) (Z) and (E) - hydroximoyl triflates (X=OSO2CF3) with a variety of nucleophiles (water, methoxide ion, amines, etc. ). Particular emphasis will be placed on determining the importance of stereoelectronic effects in the breakdown of the tetrahedral intermediates formed in these reactions.